RedisTagAwareAdapter integration

Author: l-vo

cache.rst

@@ -102,6 +102,11 @@ The Cache component comes with a series of adapters pre-configured:
 * :doc:`cache.adapter.pdo </components/cache/adapters/pdo_doctrine_dbal_adapter>`
 * :doc:`cache.adapter.psr6 </components/cache/adapters/proxy_adapter>`
 * :doc:`cache.adapter.redis </components/cache/adapters/redis_adapter>`
+* :ref:`cache.adapter.redis_tag_aware <redis-tag-aware>` (Redis adapter optimized to work with tags)
+
+.. versionadded:: 5.2
+
+    `cache.adapter.redis_tag_aware` has been introduced in Symfony 5.2.
 
 Some of these adapters could be configured via shortcuts. Using these shortcuts
 will create pools with service IDs that follow the pattern ``cache.[type]``.

components/cache/adapters/redis_adapter.rst

@@ -180,6 +180,20 @@ Available Options
     When using the `Predis`_ library some additional Predis-specific options are available.
     Reference the `Predis Connection Parameters`_ documentation for more information.
 
+.. _redis-tag-aware:
+
+Working with tags
+-----------------
+
+In order to use tags-based invalidation, you can wrap your adapter in :class:`Symfony\\Component\\Cache\\Adapter\\TagAwareAdapter`. But when Redis is used as backend, it's often more interesting to use the dedicated adapter :class:`Symfony\\Component\\Cache\\Adapter\\RedisTagAwareAdapter`. Since tag invalidation logic is implemented in Redis itself, this adapter offers better performance when using tags-based invalidation::
+
+    use Symfony\Component\Cache\Adapter\RedisAdapter;
+    use Symfony\Component\Cache\Adapter\TagAwareAdapter;
+
+    $client = RedisAdapter::createConnection('redis://localhost');
+    $cache = new TagAwareAdapter($client);
+
+
 .. _`Data Source Name (DSN)`: https://en.wikipedia.org/wiki/Data_source_name
 .. _`Redis server`: https://redis.io/
 .. _`Redis`: https://github.com/phpredis/phpredis

components/cache/cache_invalidation.rst

@@ -58,6 +58,10 @@ To store tags, you need to wrap a cache adapter with the
 :method:`Symfony\\Component\\Cache\\Adapter\\TagAwareAdapterInterface::invalidateTags`
 method.
 
+.. note::
+
+    When using a Redis backend, consider using :ref:`RedisTagAwareAdapter <redis-tag-aware>` that is optimized for this purpose.
+
 The :class:`Symfony\\Component\\Cache\\Adapter\\TagAwareAdapter` class implements
 instantaneous invalidation (time complexity is ``O(N)`` where ``N`` is the number
 of invalidated tags). It needs one or two cache adapters: the first required